The present invention relates to a new and improved construction of a refiner for processing or treating a fiber stock suspension for the fabrication of paper.
Generally speaking, the refiner for processing or treating fiber stock suspension for paper fabrication is of the type comprising at least one pair of cooperating substantially planar grinding elements or members. During the grinding or refining operation the fiber stock suspension flows between the at least one pair of cooperating substantially planar grinding elements. One of the grinding elements contains a conventional or standard set of grinding tools, sometimes also referred to herein as a grinding tool set.
The presently most widespread used refiners are the so-called disc refiners. These disc refiners possess pairs of substantially planar grinding discs which are equipped with grinding tool sets comprising confronting cutters or teeth. These cutters or teeth are formed by substantially rib-like projections or protuberances between which there are arranged grooves which extend from the inside towards the outside. Although these grooves can be designed to possess an interrupted construction in order to preclude a continuous shunted or short-circuited flow of the fiber stock suspension to the outer circumference or periphery, nonetheless a part of the fiber stock suspension is able to pass untreated through the grooves between the cutters or teeth. This flow of the fiber stock suspension is augmented by the pumping action of the grinding discs.
Furthermore, there are known in this art refiners wherein the suspension is processed or treated between conical or cylindrical elements or components which are provided with continuous or open-ended bores. Moreover, there is known a refiner construction wherein a conical grinding element, which possesses conventionally constructed rib-like cutters or teeth, coacts with a grinding element in which there are not formed open-ended bores but blindhole bores.
Yet, the construction of these heretofore known refiners is relatively complicated and expensive.
As an example of a prior art construction of refiner or grinding apparatus attention is directed to the commonly assigned, U.S. Pat. No. 4,402,463, granted Sept. 6, 1983.